This P30 Center Core Grant renewal application is a direct outgrowth of the research needs that have developed over the past 15 years by investigators at Northwestern University who are engaged in reproductive research in the areas of fertility and infertility. Fourteen investigators currently holding 25 funded NIH research grants/projects will access the four proposed scientific cores. Sixteen of these grants/projects are funded through the NICHD. The research programs to be served by the P30 Center Core Grant include investigations into the neuroendocrinology of reproduction, the regulatory mechanisms of gonadal functions, the regulatory mechanisms of gametogenesis, the mechanisms of follicular selection, the mechanisms of action of reproductive hormones, the transcriptional regulation of genes involved in reproduction, the mechanisms regulating genital track functions and the immunological mechanisms regulating fertility. Investigators in the proposed P30 Center Core Grant are currently addressing questions in the reproductive sciences at the biochemical, molecular, cellular, physiological and behavioral levels. The complexity of the life sciences in the area of reproductive research today requires the sharing of techniques and approaches that are often not available in a single research laboratory. Indeed, it is clear that major breakthroughs in our understanding of the reproductive system will require collaborative efforts of researchers who have expertise in diverse areas of research. Thus, this grant seeks to maintain three established cores (Protein Analysis, In Situ Hybridization/Molecular Technology, and Hormone and Neurotransmitter Measurement Cores), and to create one new core (Recombinant Protein Core) which will enable Core investigators to incorporate highly sophisticated techniques into their research programs in a cost-effective manner. Furthermore, the Cores will provide quality control and technical expertise in a number of different methodologies at a level normally not available to individual investigators. An Administrative Core will also be continued to administer the Center Grant. The establishment of this P30 Center Core Grant four years ago has had a major impact on the quality, quantity and cost-effectiveness of existing federally-funded research programs in the reproductive sciences at Northwestern University. It has also fostered extensive collaborations between members of the P30 Center as well as between P30 investigators and other scientists both within and outside of Northwestern. The established and new cores included in the renewal of the P30 Core Center Grant were selected because of the high impact they can be expected to have on reproductive research at Northwestern that is aimed at developing a better understanding of the regulatory mechanisms underlying fertility and infertility.